I don't know if this is jealousy or not?

I've been with my boyfriend for a little over 3 years now and were pretty much inseperable. Just recently his older brother met this new girl, and they all became obsessive over her (wanting to do everything with her, constantly talking about her and how hot she is, blahblah.) anyways, I've never clicked with his parent's, well now that this new girl came around, his parent's and his brother has been talking so much about her, and so on. The thing that just hurts me I guess is his parent's really don't get me the time of day, but when this girl comes around everyone's so happy she's there and always talking with her and it's all about her. I don't know if i'm just over-reacting or if this really is an issue?